The present invention is generally in the field of augmented reality, and relates to an optical device for use in augmented reality system. The invention can be implemented in a large number of imaging applications, such as portable DVDs, cellular phones, mobile TV receivers, video games, portable media players or any other mobile display devices. The invention can be further implemented in any type of a waveguide system that uses a total internal reflection (TIR) principle. In particular, such optical device may be incorporated within a see-through head-mounted display device (e.g. helmet- or eyeglasses-mounted display), which is a wearable display that has the capability of reflecting projected images as well as allowing the user to see through it.
In head-mounted displays (HMDs), an optical module serves both as an imaging lens and a combiner (optical mixer), and a two-dimensional image source is imaged to infinity and reflected into the eye of an observer. Such image source can be obtained either directly from a spatial light modulator (SLM) based on a cathode ray tube (CRT), a liquid crystal display (LCD), an organic light emitting diode array (OLED), a scanning source or similar devices, or indirectly using a relay lens or an optical fiber bundle. The image source typically includes a pixel matrix which is imaged to infinity by a collimating lens and is transmitted into the eye of the viewer by reflecting or partially reflecting surface(s) acting as a combiner for, respectively, non-see-through and see-through applications
Various optical devices and systems for augmented reality applications are described in the following patent publications, all assigned to the assignee of the present application and incorporated herein by reference: WO 01/95027, WO 03/081320, WO 2005/024485, WO 2005/024491, WO 2005/024969, WO 2005/124427, WO 2006/013565, WO 2006/085309, WO 2006/085310, WO 2006/087709, WO 2007/054928, WO 2007/093983, WO 2008/023367, WO 2008/129539, WO 2008/149339, WO 2013/175465 and IL 2014/232197.